Only limited evidence is available about the discontinuation rates of anti-epilepsy drugs during pregnancy. UK researchers analysed prescribing trends for anti-epilepsy drugs from 1994 to 2009, based on primary care data for 174,055 pregnancies and anti-epilepsy drug use by 745 women with epilepsy and 54 with bipolar disorder.
Prescribing of newer anti-epilepsy drugs in pregnancy has steadily increased and lamotrigine has been the most popular anti-epilepsy drug prescribed in pregnancy since 2004, whereas use of carbamazepine and sodium valproate has declined. Pregnancy was linked to discontinuation of anti-epilepsy drugs, with discontinuation rates twice as high in women with epilepsy and three times higher for women with bipolar disorder compared with non-pregnant women using anti-epilepsy medications.
What does it mean for GPs?
The authors recommend the risks and benefits of anti-epilepsy medications are explained to women – ideally prior to pregnancy – to allow them to make an informed decision on whether to continue treatment in pregnancy. They concluded: ‘Pregnancy is a strong determinant for the discontinuation of anti-epilepsy drug prescribing particularly for women with bipolar disorder.’
Dr Henry Smithson, a GP in Sheffield and the founding chair of the GP Society for Epilepsy, said: ‘There is good evidence from work in the UK and Ireland about the relative safety of anti-epileptic drugs in pregnancy. So the advice is to not change anything until you have received a specialist opinion when a women [with epilepsy] become pregnant, although that’s easier said than done. Pre-conception advice is also important. ‘